BANDAR SERI BEGAWAN, BRUNEI —
U.S. Secretary of State John Kerry is in Brunei for a regional forum of the Association of South East Asian Nations, or ASEAN. The group is hoping to agree on a legally binding code of conduct to manage a series of territorial disputes in the South China Sea among China, Vietnam, the Philippines, Taiwan, Malaysia and Brunei. The U.S. Navy is increasingly active in the South China Sea and in joint operations with the Philippines.

U.S.-Philippine naval cooperation includes unmanned surveillance of waters under dispute with China.

"The unmanned aerial vehicle will be a very very important tool in our operations in safeguarding the entire maritime territory," said Philippine Navy Lieutenant Rommel Rodriguez.

China is especially concerned about Philippine plans to upgrade the former U.S. naval base at Subic Bay, just 240 kilometers from a disputed shoal that China has controlled since 2012.

China's Communist Party newspaper said a "counterstrike" against the Philippines is inevitable if Manila continues what Beijing calls "unscrupulous" tricks.

"China urges the Philippines and regional countries to meet one another halfway, make joint efforts to maintain mutual trust between countries, make positive efforts towards regional peace and security and play a constructive role," said Chinese Foreign Ministry spokeswoman Hua Chunying.

Washington said it is not taking sides in the South China Sea and wants to help resolve the disputes peacefully as part of its refocusing on Asia.

"It's certainly part of the rebalance that the U.S. is looking to reinforce not only militarily but economically and politically with Asia," said U.S. Rear Admiral Thomas Carney.

A more active U.S. Navy with a Visiting Forces Agreement in the Philippines is an important check on China, says University of the Philippines professor Clarita Carlos.

"Given all the provocations from China in trying to get for herself all those islands, reefs, etc., and other features in the South China Sea, I think this is one way of telegraphing to her, we also have the capability if we want to, of course supported by the United States of America," Carlos explained.

But a more aggressive Philippines may make China even less willing to compromise, says American University professor Pek Koon Heng.

"It's going to make it even more difficult. It's going to just harden the Chinese position about working with ASEAN," he added.

Heng expects this year's ASEAN ministerial in Brunei to be far different from last year's meeting in Cambodia where China helped scuttle a code of conduct for the South China Sea.

"Secretary Kerry has got an ASEAN that is more cohesive after China divided ASEAN in the last foreign minister meeting," Heng said.

Foreign ministers at this meeting are also expected to discuss the war in Syria, as well as a U.S. surveillance program leaked by former intelligence analyst Edward Snowden.